A liquid crystal display device has advantages of low voltage, low power consumption, large amount of display information and easy to be colorized, and has been widely used in electronic devices, such as electronic computers, electronic notepads, mobile phones, cameras and high-definition televisions. A liquid crystal display device generally includes a liquid crystal display panel for displaying a picture and a circuit for providing signals to the liquid crystal display panel. The liquid crystal display panel generally includes a Thin Film Transistor (TFT) array substrate, a color film substrate and a liquid crystal layer which comprises liquid crystal molecules disposed between the array substrate and the color film substrate.
In general, the TFT array substrate is provided with multiple video signal lines (also referred to as data lines) and multiple scanning lines (also referred to as gate lines) intersecting the video signal lines, multiple regions are formed on the TFT array substrate by the video signal lines and the scanning lines. Each of the regions is provided with a pixel electrode and a switching element TFT for selectively providing video signals to the pixel electrode. The switching element TFT and the pixel electrode form the pixel unit.
On the TFT array substrate, a signal on the gate line plays an important role to display for the liquid crystal display panel, for example, it is configured to drive each pixel unit to be turned on or turned off. However, presently whether the signal on the gate line is operational can only be detected manually one by one, thereby resulting in low efficiency; and with an increase in density of the gate lines, the method for manually detecting whether the signal on the gate line is operational becomes less effective.